Means for sharpening bits



April 24, 1945. F. MCCARTHY. JR 2,374,362

MEANS FOR SHARPENING BI TS Filed Dec. 7, 1942 3 Sheets-Sheet l w mW l JAMES F. m: cARTmwa' INVENTOR ATTORNEYS April 1945- J. F. MCCARTHY. JR I 2,374,362

H Z I BY ATTORNEYS MEANS FOR SHARPENING BITS Filed Dec. 7, 1942 '3 Sheets-Sheet 2 Q A I I3 F/G. 3

2\ 3 I I l d v\ w J u JAMES M A \Y/ A F .NVEM

April 24, 19 5. J. F. M CARTHY. JR I 2,374,362

MEANS FOR SHARPENING BITS Filed Dec. 7, 1942 5 Sheets-Sheet 5 W! JAMES F.,M,QN1%RTHY' J ATTORNEYS Patented Apr. 24, 1945 UNlTED STATES FATENT OFFIQE} 2,374,362 MEANS FOR SHAR PENING BITS James F. McCarthy, Jr., Wallace, Idaho Application December 7, 1942, Serial No. 468,121

3 Claims.

The present invention relates to means for sharpening bits and in more particular relates to a device for use on a rock-bit milling machine.

As is well known in the art, such rock-bits ordinarily'have a plurality of radial wings for cutting action. The bits are resharpened by inserting a milling tool between the wings and reshaping the wings and the cutting edges. In the sharpening operation, the bit is mounted on a spindle which is swung so that the miller will enter between the wings and perform the sharpening operation.

In the past, the indexing of bits upon a bit holder has either been performed manually or mechanically. The manual operations, while satisfactory to a limited degree, are subject tosevere criticism by boards of safety due to the fact that the operators hand has to be brought into close proximity with high-speed rotary elements. The mechanical indexers heretofore available have been unsatisfactory primarily from the standpoint of their complexity and. consequent great cost. In addition, the prior mechanical indexing means taught a construction that prevented their adaptation to equipment of the type to which this invention pertains.

Having in mind these defects of the prior art. it is an object of the present invention to provide an indexing means for rock-bits in sharpening machines.

A further object of the present invention is to provide an indexing means for rock-bit sharpening machines which will accurately index the bit to the proper position.

A further object of the present invention is theprovision of an indexing means for rock-bit milling machines. which indexin means will require a minimum of manual attention.

The aforementioned obiects of the invention are attained and the defects of the prior art remedied by providing a bit holder of the prior art with an indexing wheel and a locking ratchet; the indexing wheel to be engaged by an adjustable indexing arm, and the locking ratchet to be engagedby a locking pawl. Back and forth operation of the swinging bit holder with a bit placed thereon, to the miller brings the indexing wheel into engagement with the indexing-arm to rotate the bit supporting spindle and to bring the bit into proper registry for milling. The locking pawl, or detent, will hold the spindle in position and prevent reversing of the motion of the spindle. As the tool holder is withdrawn from the milling wheel it will ratchet past the indexing arm, which is spring mounted, and be in position for again returning to the miller with a further indexing movement;

Other objects and advantages which reside in the invention are disclosed in the details of design and construction, which will be more fully disclosed by the following description and the drawings, wherein: Figure 1 is an end view of a portion of a milling machine showing a milling cutter, a tool holder, and indexing means, with portions of the tool holder in section;

Figure 2 is similar to Figure 1, with the parts shown in elevation;

Figure 3 is a front elevational view of the apparatus shown in Figures 1 and 2;

Figure 4 is a perspective view of an indexing wheel and its supporting spindle;

Figure 5 is a sectional view on the line 5-5 of Figure 1, and shows a locking ratchet; Figure 6 is a sectional view of an indexing-arm post;

Figures '7 to 12, inclusive, are plan views showing various relative operating positions of the indexing wheel and indexing arm, in relation to each other and to the milling wheel.

Figure 1 shows an end view of the milling wheel l, which is suitably supported on an appropriate arbor A and hearings in fixed relation to a shaft 2 which carries secured thereto, by appropriate keys, a bit holder head 3. The shaft 2 is suitably journaled for rotation. I

Also secured to the shaft is an operating handle 4 by means of which the shaft may be rotated, and the bit holder post swings about the axis of shaft 2 in a manner to bring a bit supported on the holder into contact with the milling wheel I. The bit holder arm 5 is bearinged in a suitable sleeve 6 supported by a casting EA attachedto the head 3. The bit holder is composed of a boss 1, an indexing wheel 8 and a locking ratchet 9.

The casting EA is adapted to contain therein a spring-pressed locking detent ID for engagement with the locking ratchet 9.

An indexing detent H is secured in shaft 12, whichis carried in a bracket [3 in fixed relation to the arbor carrying the milling wheel I. A spring I4 is coiled around the indexing arm pin l2 to give it clockwise motion looking down from above as in Figures 7-12. The bracket i3 carries a stop i5 against which the indexing detent H is brought to rest by the spring M. The location of the bracket [3 is adjustable, as is the length of the indexing detent H, so that some adjustment of the operation of the indexing wheel maybe had.

In Figure 1 the under face of the wheel 8 is shown as having an annular recess I! which receives the upper end extension l8 of the bushing to form a dust seal at this point to protect the bearing surfaces within the bit holder arm. In 5 such sharpening operations as are performed with equipment of this nature a great quality of fine metallic dust flies about and has an abrasive action upon bearing surfaces between which it may becomelo'dged. As shown in Figure 1, there- 10 fore, the wheel 8 serves not only for ratcheting of the pin, but as a deflector and seal for the internal bearing thereunder.

The parts are so mounted with respecttdeach other and so shaped that when"a rock-bit--is placed on the boss of the bit holderpostand the handle 4 is swung to present the bit to the milling wheel, one of the teeth of the ratchet'wheel 8 will have its face contacted by the indexing detent II which will cause the indexing wheel to move an angularsdistance i equalfitonone of tits segments as shown in Figuresi'lthroughlmo. :This :movement of thei.-bitlholder .-postewi=llzcause the detent 10' to be: retracted: fromionezofltheilocking 1 ratchet indentationsimandltoudropzin and: engage" positive chucking means. This means that for the first cut the bit may not come into exact registry with the milling wheel, but the uneven pressure of the milling wheel with respect to the two adjacent wing surfaces will align the bit properly with the milling wheel. Further forward and backward movement of the holder will produce accurate indexing of the bit to the further faces to be milled.

i Having thus :describedmy invention,- I claim:

1. In:a rock bit sharpening machine of the type employing a rotary sharpening wheel, a yrotatable bit holder pin having secured thereto an indexing wheel, a locking ratchet on said pin, means for supporting said pin for swinging move- -mentto and-from a sharpening wheel of said machine, an indexing detent pivotally supported, =a=stop -against which said indexing detent rests wto immovably hold the same in the path of the forwardly moved indexing wheel, spring means ixto normallyrhold'said indexingidetenhagainst said stop: but; permitting the indexing ,-detent. to. swing from thew-stop upon'rearwardmotions-of the i-ncdexingwheeL-and adetentengageable in the locking ratchet iOf' said bit :holder pin. to locln the ninexthe nextriadlacenthzone. This detentolflizznd same1against:counter-indexing:movementvof the the locking ratchet 9 are so shapednthatathexpost -1 can: be rrotateduinoner direction .only. T-iThey .ZISOL are so shaped: andxthe sspring": pressure: is

upin: during; rearward movementi of the indexing .wheel past the-indexingdetent. v

:2. In a rock bitlshar p ningmachine ..of the :such that the;post;is -held securelyzenoughfimposi'- type employing a--rotary,sharpeningtwheel,ta;,bit

tion that the milling of the bittmillz'be. true.

:After the: facerbetween twona'diacentwwings on the bit has been milled, the handlextais withdrawn uandnthe ib tvandxholden areaelsosthercbyr withdrawn. In withdrawin ,'zthenindexingwheel will-contacttheback siderofi-the indexingcdet n H and be caused-tormtate-aboutitssaxis ta leave the stop; l5,- and tor-rotate.tha llpp rtmgwi 12 a ainst thaactiom ofs h 51 131 25 4. i' fh s'imotion is detailed lmll'igure; 12; iwhereindexina \detent I I is shown to allow the indexing wheel to passnupon whichthe arm will thenabe-gsmfing urged-against the-stop l 5, r and be: heldnimposition forr the, next forward; movement-poi; the bit, holder and-shit: to

holder, pin having secured theretoa flange immediatelybelowthe.pointatswhioh a bit isv supported ,thereon,. teeth, on, said fiangeeconstitutingn an inidexingwheel, means. ior .supporting.-said..pm and t irmluding,a..journaLshieldedby saldtfiange; from cuttings, of the, sharpening operation, an indexin defiant .pivotallyr supportedand. positioned inlthe 'iorwardpath fithe indexin w e stop m ans tohold said indexing detent immovably upon for- 40 ward; movement of the indexing wheel whereby the latter is causedto rotate, andspring, means to normally hold the indexingdetent; against its stop but permitting the indexing detent" 'toswj'ng "from' the stop upon rearward -movement--of the the milling ,wrheel, when the; bit willa i b indexing wheel andpin.

indexed to, the next cuttinef-. position.

, From, the above descriptionofithe partsiof the present deviceandutheir; operatiomitiszapu 'rent 1 thatapplicant hasfidevisedanindexing .means dor 3. In a rockhbit--sharpen-ing machine of the type=employing-- a-rotary shar peningi wheel; a bit holder: pin having Y secured" thereto -=an indexing "wheel; meansforsupporting 1 said pin 'fio'ri :Swing- :a, rockebiti holderewhichineedsqfa ;minimum; of 5o ing movement to and from the sharpeningavheel manual operation and skill. !All,that isinecessary is the. placing ofthebitnpon the holding ,post and the successive ,operationbftthe arm.4 ,tohring, the bite into .contact .withothe. milling .wheel. -.,\Motion .of the..arm causingthe,hack,and;vforth 21110121011 of c the, holder acts ,to automatically ,index athe 1 holder .to the various requiredpositions. {The-bit is loosely carriedaon' the suppereend of ,..the shit holder post andis notsecured thereto .as-by some ol; the rmachine anindexing detent 'pivotallyisupportedi and positionedin the path of theindexing wheeL-a stop-against which saidindexingqdetent rests to immovably hold therisametupon ionward .movement .of l the indexing .wheel, .and spring vmeans itoinormally. hold:thedetent against-its stopbut permitting the .detent to swing from, the

stop upon rearwardmovement ofathe rwheel. 

